Chemistry of Class 1 CRISPR-Cas effectors: Binding, editing, and regulation

J Biol Chem. 2020 Oct 16;295(42):14473-14487. doi: 10.1074/jbc.REV120.007034. Epub 2020 Aug 14.


Among the multiple antiviral defense mechanisms found in prokaryotes, CRISPR-Cas systems stand out as the only known RNA-programmed pathways for detecting and destroying bacteriophages and plasmids. Class 1 CRISPR-Cas systems, the most widespread and diverse of these adaptive immune systems, use an RNA-guided multiprotein complex to find foreign nucleic acids and trigger their destruction. In this review, we describe how these multisubunit complexes target and cleave DNA and RNA and how regulatory molecules control their activities. We also highlight similarities to and differences from Class 2 CRISPR-Cas systems, which use a single-protein effector, as well as other types of bacterial and eukaryotic immune systems. We summarize current applications of the Class 1 CRISPR-Cas systems for DNA/RNA modification, control of gene expression, and nucleic acid detection.

Keywords: CRISPR-Cas; DNA endonuclease; archaea; bacteria; bacteriophage; crRNA; cyclic nucleotide; enzyme mechanism; gene regulation; genome editing; prokaryotic adaptive immunity; ribonuclease.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Adenine Nucleotides / metabolism
  • Animals
  • CRISPR-Cas Systems / genetics*
  • DNA / chemistry
  • DNA / metabolism
  • Gene Editing*
  • Gene Expression
  • Oligoribonucleotides / metabolism
  • RNA / antagonists & inhibitors
  • RNA / metabolism
  • RNA, Guide / metabolism
  • Signal Transduction


  • Adenine Nucleotides
  • Oligoribonucleotides
  • RNA, Guide
  • 2',5'-oligoadenylate
  • RNA
  • DNA